Do you think certain color or tail types live longer, or are more likely to act a certain way?
Kinda like cats...I found black and white cats (andBW mutt dogs, not full breeds..and BW horses) to have more outgoing & quirky personalities, ginger ones more expressive, etc.
I think there is some truth..a siamese is the same species as a maine coon, but siamese are famously way more talkative.

My friend has 6 bettas & the oldest is 4 years, a red crowntail male. :)
She swears they are the most aggressive.
Granted, I don't have as much experience...but out of all mine...the dalmation VT
is the only only who practically rips my finger off for pellets, and has tried to jump like a champ
during water change moves.
I got Danny Boy @ about 3 months old, and he's always been super friendly, swimming right
into the moving cup, not scared of anything. The double tail pastel acts the same, he's young looking too.
The Dragon Delta is the most skittish & hates changes.

Our black and white cat is totally more of the 'stare at you from a distance' type, though I don't know! XD He's only friendly if you have ham(someone fed it to him once as a kitten..now he won't leave us alone about it!) I don't really know so much about fur affecting personality as much, though sometimes certain fur colors tend to always get the same illnesses-white fur, skin problems, etc.

I think it depends on the type of animal--with some species color morphing only comes through a ton of inbreeding, this can lead to different levels of intelligence and health which can also affect their personalities. I know some breeds of small birds--the natural colors are always feistier while the bright morphs can sometimes be a little less intelligent--of course this isn't all species or even all of the specific types I've mentioned!

It's possible reds could be healthier, I know that red is a very powerful color and it takes generations to sometimes fully get red out of the betta--which could weaken the animal, if even just slightly!

But it probably just depends on the line the betta came from--Like, lets talk petstore breeders. Many not taking the best care of their fish, probably not trying as hard to get the healthiest fish out there. If reds are easier to make, they will probably end up being some of his healthiest! If the same irresponsible breeder were to try to make more complex colors of bettas look nice, they might not be as healthy seeing as he would be using mediocre raising methods(just to make money after all!)

But then if you had a smart breeder who knew what they were doing, I think any color could be just as spunky as the others! So I dunno, this is all sort of me brainstorming, I guess it could go either way.

Of course I still am waiting for my first betta so I can't really participate in this conversation yet :)